The purpose of this study is to use fMRI to investigate whether the brain response to acupuncture depends primarily on the meridian origin or on the segmental innervations of the acupoint. Whether different acupoints exert effects that are distinct from one another (acupoint specificity) is an important but unsettled issue in acupuncture theory and practice. In this study the acupoint specificity is tested in 18 healthy adults by comparing two acupoints of different meridians and a sham point, all of which are in the same neural segment, and a fourth acupoint that differs both in meridian and in segmental innervarions from the acupoints above. Whole brain fMRI is performed during electroacupuncture at St36 (Zusanli),Gb34 (Yanglingquan) and a sham point on the leg, and at Li11(Quchi) on the elbow. The fMRI data are analyzed to identify regions that may be activated or deactivated, and to quantify the signal changes. The hemodynamic response will be correlated with the meridian and segmental innervations of the acupoints. My long-term goal is to find more evidence to elucidate the central neurophysiological mechanism of acupoint specificity. This will help provide a scientific guideline for the selection of acupoints in clinical practice and experimental studies.